QUOTE(maximR @ Dec 12 2012, 10:28 PM)
Why does the product of heads and tails permit hydrophobic molecules from moving across the plasma membrane , but not polar ones ?
Does that mean hydrophobic molecules are unaffected by the polar heads ? Sorry , my biochemistry is still not that solid .
Where do you normally buy your textbooks / reference books ? Kinokuniya ? They are pretty expensive .
I also bought a CIE AS / A Level Economics book , the one that's endorsed by CIE . SAT Literature by Princeton , SAT Biology E/M by Kaplan , IB Geography ( it was priced at RM8
) , SAT Subjects Test Official Book by CollegeBoard , Economics for IGCSE and O Level ( the older version ) , Barron's Physics ( just a physics textbook , not a test prep book ) and Cliff Note's Biology Study Solution .
I didn't buy the AP books and when I went back the second time , they were all gone . My friend who went there to get his IB books , got 4 which are Maths SL and HL , Economics , English Literature and Biology and several more A Level books .
I just didn't have luck that time .
I saw many parents buying IB books for their children . Didn't know there were so many IB students in Malaysia , especially around Selangor . I also talked to a guy who recommended AP instead of IB . I'm still unsure . He said I could self study for it , and it is an equivalent to any one of the traditional pre-u courses . Is this true ?
I really like how these IGCSE topics are organised , especially the chemical analysis part ( how to prepare and collect gases , test for ions , etc . They were really comprehensive . ) Wish I could grab hold of more IGCSE books for a lower price .
Like property (in this context, hydrophilic or hydrophobic) attracts each other, in such a way, hydrophilic molecules are atrracted to hydrophilic molecules and vice-versa.
The phospholipid bilayer suggests hydrophilic heads, and hydrophobic tails, alligned in opposite sequence with tiny openings between them.
So, hydrophobic molecules have no problem entering via the bilayer as there is a long region of hydrophobic tails.
The hydrophilic heads are relatively too small to repel the molecules compared to the longer hydrophobic tails.
Hydrophilic molecules are repelled heavily by the longer hydrophobic tails, so not manage to travel through.
This makes plasma membrane impermeable to hydrophilic molecules, but selectively permeable to hydrophobes.
All that, plus the potential difference in concentration gradient, forces that either one must go through.
Good start with your tertiary education with those books.
AP allows private candidates, which means self-study is possible so there is no definite requisite for schooling, and enables full flexibility in choices. In comparison, one cannot take up the IB if not enrolled in any IB World schools, so no self-study is possible.
IB also limits flexibility by imposing a must on 6 subjects, all of different fields.
That is good to produce a wholesome student, from a non-competitive community. However, the problem lies in not allowing students to take more than 6 subjects, or the gifted to take more than 4 HL subjects.
Internationally, AP is regarded equally as IB, however, unofficially, I believe most are more impress with one having the IB Diploma.
Dec 9 2012, 06:10 PM
Pure science (9 subjects) + ICT
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